Measuring probe and living body optical measuring device

ABSTRACT

In a measuring probe, the distal ends of an irradiation optical fiber and a detection optical fiber on the subject side are held by a holder portion which is to be mounted on a subject. The optical fibers are led out from the side surface of the holder portion. Further, the optical fibers are bent in the holder portion so that the distal ends of the optical fibers are directed towards the subject when the holder portion is mounted on the subject.

TECHNICAL FIELD

The present invention relates to a measuring probe adapted to irradiatea subject with measurement light and receive light transmitted throughthe subject (living body passing light), and to a living body opticalmeasuring device having the measuring probe.

BACKGROUND ART

As disclosed, for example, in JP 9-98972 A, a conventional living bodyoptical measuring device has a measuring probe attached to a subject anda device main body connected to the measuring probe. The measuring probehas an irradiation optical fiber for irradiating the subject withmeasurement light generated in the device main body, a detection opticalfiber for receiving the measurement light transmitted through thesubject, that is, a living body passing light, and guiding it to thedevice main body; a fixing member for securing the distal end portionsof the irradiation and detection optical fibers at predeterminedpositions of the subject; and a fixation belt for securing the fixingmember to the subject.

However, in the case, for example, of the measurement of a newborn babyor a measurement of long duration, it is necessary to perform, apartfrom a measurement in a seated position or a standing position,measurement in which the subject lies down, and there is demand for ameasuring probe allowing such measurement. That is, there is demand fora measuring probe which can be attached to the subject without damagingthe optical fibers even when the subject lies down.

DISCLOSURE OF THE INVENTION

The present invention has been made with a view toward solving the aboveproblem. It is accordingly an object of the present invention to providea measuring probe and a living body optical measuring device which allowmeasurement with a subject lied down.

To this end, according to one aspect of the present invention, there isprovided a measuring probe comprising: a holder portion attached to asubject; and an optical fiber for at least one of irradiation anddetection whose distal end portion on a subject side is retained by theholder portion, wherein the optical fiber is led out from a side surfaceof the holder portion and is bent inside the holder portion such thatthe distal end portion is directed to the subject when the holderportion is attached to the subject.

According to another aspect of the present invention, there is provideda living body optical measuring device comprising a measuring probehaving a plurality of optical fibers that irradiate a subject withmeasurement light and receive the measurement light returning from thesubject, the measuring probe being attached to the subject, wherein theoptical fibers are led out from a side surface of the measuring probeand are bent inside the measuring probe portion such that their distalend portions are directed towards the subject when the measuring probeis attached to the subject.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a measuring probe according to Embodiment 1 ofthe present invention;

FIG. 2 is sectional view of a holder portion of FIG. 1;

FIG. 3 is a plan view of FIG. 2 with a holder cover removed;

FIG. 4 is a plan view of a holder base of FIG. 2;

FIG. 5 is a side view of the holder base of FIG. 4;

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 4;

FIG. 7 is a bottom view of the holder base of FIG. 4;

FIG. 8 is a sectional view of the holder cover of FIG. 2;

FIG. 9 is a bottom view of the holder cover of FIG. 7;

FIG. 10 is a block diagram schematically showing the construction of aliving body optical measuring device including the measuring probe ofFIG. 1;

FIG. 11 is a front view of a measuring probe according to Embodiment 2of the present invention;

FIG. 12 is a sectional view taken along the line XII-XII of FIG. 11;

FIG. 13 is a perspective view of the measuring probe of FIG. 11 with theholder cover removed therefrom;

FIG. 14 is a perspective view of the holder portion of FIG. 11 asattached to a subject;

FIG. 15 is a perspective view of the holder portion of FIG. 14 with afastening fixing member attached thereto from above;

FIG. 16 is a plan view of a measuring probe according to Embodiment 3 ofthe present invention; and

FIG. 17 is a plan view of a measuring probe according to Embodiment 4 ofthe present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, preferred embodiments of the present invention will bedescribed with reference to the drawings.

Embodiment 1

FIG. 1 is a plan view of a measuring probe according to Embodiment 1 ofthe present invention. In the drawing, the measuring probe of thisembodiment has a probe main body 101 to be attached to a subject, aplurality of irradiation optical fibers 102 for guiding irradiationlight from the main body of a measuring device to the probe main body101, and a plurality of detection optical fibers 103 for guiding livingbody passing light from the subject to the main body of the measuringdevice.

Unlike the conventional measuring probes, the measuring probe of thisembodiment has the irradiation and detection optical fibers 102 and 103attached in advance to the probe main body 101. Thus, by attaching theprobe main body 101 to the subject, the irradiation and detectionoptical fibers 102 and 103 are respectively arranged at desiredmeasurement positions. That is, by placing the probe main body 101 onthe head of the subject, the irradiation and detection optical fibers102 and 103 are respectively arranged at desired measurement positions.

One end (distal end) of each of the irradiation and detection opticalfibers 102 and 103 is retained perpendicular to the surface of thesubject with which the probe main body 101 is brought into contact.Also, the irradiation and detection optical fibers 102 and 103 are drawnout of a side surface of the probe main body 101. The other end of eachof the irradiation and detection optical fibers 102 and 103 is connectedto the measuring device main body.

The probe main body 101 has three holder portions 104. In each holderportion 104, three optical fiber head portions (including an irradiationbed portion and a detection bed portion) are provided at equalintervals. The holder portions 104 are connected together atpredetermined intervals by connecting portions 105. As a result, theintervals between the holder portions 104 are maintained, and themeasuring probe as a whole is reduced in weight and thickness.

Further, in order that the attachment position of the measuring probe isnot shifted even if the subject moves in a horizontal position, such asa prone position, a fixing means (not shown), such as a belt, forsecuring the measuring probe to the head may be connected to the probemain body 101.

Next, FIG. 2 is a sectional view of the holder portion 104 of FIG. 1,FIG. 3 is a plan view of FIG. 2 with a holder cover removed, FIG. 4 is aplan view of a holder base shown in FIG. 2, FIG. 5 is a side view of theholder base of FIG. 4, FIG. 6 is a sectional view taken along the lineVI-VI of FIG. 4, FIG. 7 is a bottom view of the holder base of FIG. 4,FIG. 8 is a sectional cover of the holder cover of FIG. 2, and FIG. 9 isa bottom view of the holder cover of FIG. 7.

In the drawings, placed on a holder base 201 constituting a first memberis a holder cover 202 constituting a second member. The holder base 201is arranged on the side to be brought into contact with the subject, andthe holder cover 202 is arranged on the side not to be brought intocontact with the subject. The holder base 201 is formed of a materialmore flexible than that of the holder cover 202. The holder cover 202 isformed of a material more rigid than that of the holder base 201.

Between the holder base 201 and the holder cover 202, there are retainedthree optical fibers 102 and 103. A plurality of mutually independentoptical fiber arranging grooves (protecting grooves) 207 in which theoptical fibers 102 and 103 are accommodated are provided in the holderbase 201. Further, the optical fibers 102 and 103 are introduced intothe holder portion 104 through a side surface of the holder portion 104,and extend within the holder portion 104 in the direction in which theholder portion 104 extends, with their distal end portions being bentsubstantially at right angles.

Inside the holder portion 104, there are provided a plurality of opticalfiber fixing members 203 for securing the distal ends of the opticalfibers 102 and 103, a plurality of optical fiber protecting members 204for protecting the bent portions of the optical fibers 102 and 103, anda plurality of height adjustment jigs 205 for adjusting the amount bywhich the optical fibers 102 and 103 protrude from the holder base 201.

The optical fiber fixing members 203 retain the optical fibers 102 and103 such that the distal end portions of the optical fibers 102 and 103are arranged at the measurement positions of the subject. Further, theoptical fiber fixing members 203 have built-in spring mechanisms (notshown) which retain the optical fibers 102 and 103 and extrude them by aminute amount from the surface of the holder base 201.

The optical fibers 102 and 103 are arranged so as to avoid the opticalfiber fixing members 203 for the other optical fibers 102 and 103. Forexample, the optical fiber 103 arranged at a position nearest to theintroducing portion for the optical fibers 102 and 103 passes a sidenear a first protrusion 402 a (described below) for fixing together theholder base 201 and the holder cover 202, and is bent vertically by theoptical fiber protecting member 204 before being retained by the opticalfiber fixing member 203. The optical fiber 102 arranged at theintermediate position passes the outer side of the optical fiber 103closest to the introducing portion, and, after being vertically bent bythe optical fiber protecting member 204, is retained by the opticalfiber fixing member 203. Further, the optical fiber 103 arranged at theposition farthest from the introducing portion of the above opticalfibers 102 and 103 passes the side opposite to the above-mentioned twooptical fibers 102 and 103 with respect to the first protrusion 402 a,and is bent vertically by the optical fiber protecting member 204 beforebeing retained by the optical fiber fixing member 203.

The above arrangement of the optical fibers 102 and 103 are effected byinserting the optical fibers 102 and 103 into the optical fiberarrangement grooves 207. In this process, in order to make the bendingrate when bending the optical fibers 102 and 103 while protecting themby means of the optical fiber protecting members 204 as low as possible,the outer peripheral coatings of the optical fibers 102 and 103 areremoved, and the core portions of the optical fibers 102 and 103 arearranged in the optical fiber arrangement grooves 207.

In the mating surface of the holder base 201 (the surface mated with theholder cover 202), there are provided three recesses 401 with a circularsection. At the bottom of each recess 401, there is provided athrough-hole 402 leading to the subject side. The distal end portions ofthe optical fibers 102 and 103 are protruded slightly out of the holderbase 201 through the through-holes 402.

The recesses 401 and the through-holes 402 are arranged coaxially. Thediameter of the recesses 401 is larger than the diameter of thethrough-holes 402. As a result, step portions are formed at the bottomof the recesses 401. Further, the diameter of the recesses 401 is thesame size as the outer peripheral diameter of the height adjustment jigs205 and of the optical fiber fixing members 203. The height adjustmentjigs 205 and the optical fiber fixation jigs 203 are inserted into therecesses 401.

Further, the holder base 201 has a plurality of annular protrusions 403protruding so as to surround the distal end portions of the opticalfibers 102 and 103 exposed from the holder base 201. By adjusting theamount by which the optical fibers 102 and 103 protrude with respect tothe annular protrusions 403 by the height adjustment jigs 205, it ispossible to adjust the pressurizing force with which the distal endportions of the optical fibers 102 and 103 abut the subject. Further,due to the annular protrusions 403, external light is prevented fromentering the optical fibers 102 and 103 during measurement.

Further, the annular protrusions 403 are formed independently of eachother and arranged so as to be spaced apart from each other. As aresult, when the measuring probe is arranged on the subject, deformationof the holder portion 104 is allowed such that the annular protrusions403 are in conformity with the measurement region (abutment region). Asa result, it is possible for the optical fibers 102 and 103 to abut thesubject at right angles or substantially at right angles. Further, dueto the deformation in conformity with the configuration of themeasurement region, external light is more reliably prevented fromentering the optical fibers 102 and 103 during measurement.

While in this example the external configuration of the annularprotrusion 403 formed at the center is circular, and the externalconfiguration of the annular protrusion 403 arranged on either sidethereof is elliptical, the configurations of the annular protrusions 403are not restricted thereto.

The height adjustment jigs 205 prevent excessive burden on the opticalfibers 102 and 103 when the moving amount of the optical fibers 102 and103 at the time of attachment of the measuring probe to the subjectexceeds the deformable range of the built-in spring mechanisms of theoptical fiber fixing members 203. This helps to prevent the opticalfibers 102 and 103 from being damaged.

At the longitudinal ends of the holder base 201, there are formedrelatively large first protrusions 402 a. Further, between (in theinterval) of the recesses 401 adjacent to each other, there are formedsecond protrusions 402 b whose section diameter and protruding amountare smaller than those of the first protrusions 402 a.

In the mating surface of the holder cover 202 facing the holder base201, there are formed a plurality of accommodating portions 404, whichare recesses opposed to the recesses 401. The recesses 401 and theaccommodating portions 404 define spaces for accommodating the bentportions of the optical fibers 102 and 103. The accommodating portions404 accommodate the bent portions of the optical fibers 102 and 103, theoptical fiber fixing members 203, and the optical fiber protectingmembers 204. The size of the accommodating portions 404 is set so as tobe minimum within the range not involving damage due to the bending ofthe optical fibers 102 and 103.

Further, the movement of the optical fibers 102 and 103 due to themovement of the distal end portions of the optical fibers 102 and 103when attaching the measuring probe to the subject is absorbed by thebent portions accommodated in the accommodating portions 404. As aresult, the burden on the optical fibers 102 and 103 is substantiallyreduced, thereby preventing the optical fibers 102 and 103 from beingdamaged.

Further, the inner peripheral surfaces of the accommodating portions 404are formed in the same size and configuration as the outer peripheralsurfaces of the optical fiber fixing members 203. That is, theaccommodating portions 404 also serve as retaining means for retainingthe optical fiber fixing members 203. As a result, when the measuringprobe is attached to the subject, positional deviation of the opticalfiber fixing members 203 is prevented, making it possible to obtain moreaccurate measurement results.

In order to make the holder cover 202 as thin as possible and to ensurea sufficient strength, protrusions are formed in those portions of thesurface thereof on the opposite side of the mating surface (the portioncoming into contact with a bed, etc. at the time of measurement) inwhich the accommodating portions 404 are formed.

In the holder cover 202, there are formed a plurality of grooves 405through which part of the bent optical fibers 102 and 103 pass. Thegrooves 405 extend from the accommodating portions 404 in the samedirection as the optical fiber arrangement grooves 207. The opticalfibers 102 and 103 are partially retained in the grooves 405, wherebythe optical fibers 102 and 103 are bent in minimum spaces, and theburden on the optical fibers 102 and 103 is minimized.

Further, in the holder cover 202, there are formed two insertion holes406 a into which the first protrusions 402 a are inserted, and twojoining recesses 406 b into which the second protrusions 402 b arefitted. By inserting the first protrusions 402 a into the insertionholes 406 a and by fitting the second protrusions 402 b into the joiningrecesses 406 b, the holder base 201 and the holder cover 202 arecombined with each other. Further, the holder cover 202 is fixed to theholder base 201 by screws or the like.

Next, FIG. 10 is a block diagram schematically showing the constructionof a living body optical measuring device including the measuring probeof FIG. 1. In the drawing, the living body optical measuring device hasa probe main body 101, a light source portion 501, an oscillatingportion 503, a plurality of photo diodes 511, a lock-in amplifier module512, an A/D converter 516, a control portion 517, an input/outputportion 502, and an image producing portion 521.

The light source portion 501 has a plurality of (for example, four, asin this case) optical modules 502. Each optical module 502 has twosemiconductor lasers (not shown) respectively emitting lights of aplurality of wavelengths from the visible to the infrared wavelengthregion, for example, dual wavelengths of 780 nm and 830 nm.

All the semiconductor lasers included in the light source 501 aremodulated by the oscillating portion 503 composed of oscillators ofdifferent oscillation frequencies. That is, in the oscillating portion503, the semiconductor lasers are analog-modulated by a sine wave.Further, each of the optical modules 502 is equipped with an opticalfiber connector (not shown) introducing the lights of the wavelengths of780 nm and 830 nm emitted from the semiconductor lasers into a singleirradiation optical fiber 102.

Thus, the light consisting of a mixture of lights of two wavelengthsemitted from the light source portion 501 is applied to the subjectconstituting the object of irradiation from the distal end portions of aplurality of irradiation optical fibers 102 connected to each of theoptical modules 502. At this time, the irradiation optical fibers 102are secured in position at the probe main body 101 as stated above, andapply light to different positions. For example, the distal end portionsof the irradiation optical fibers 102 and the detection optical fibers103 are arranged alternately in a tetragonal-lattice-like fashion insidethe probe main body 101.

The living body passing light (the light transmitted through a lightscattering reflective body) returning from the subject is detectedthrough a plurality of (for example, five) detection optical fibers 103arranged in the probe main body 101 by photo diodes (photo detectors)511 connected to the other ends of the detection optical fibers 103. Asthe photo diodes 511, it is desirable to adopt well-known avalanchephoto diodes which allow high sensitivity optical measurement.

The living body passing light is converted to electric signals (livingbody passing light intensity signals) by the photo diodes 511.Thereafter, a modulation signal corresponding to the irradiatingposition and wavelength is selectively detected by a modulation signalselective detection circuit, for example, a lock-in amplifier module 512composed of a plurality of lock-in amplifiers (not shown).

At this time, the modulation signals output from the lock-in amplifiermodule 512 are ones respectively separated into living body passinglight intensity signals corresponding to the wavelengths and irradiatingpositions. In the lock-in amplifier module 512, there are used the samenumber of lock-in amplifiers (not shown) as the number of signals to bemeasured (for example, 24).

The living body passing light intensity signals analog-output from thelock-in amplifier module 512 are respectively converted to digitalsignals by an A/D converter (analog/digital converter) 516 of aplurality of (for example, 24) channels. The digital signals are livingbody passing light intensity signals respectively corresponding to thewavelengths and irradiating positions.

The light source portion 501, the oscillating portion 503, the lock-inamplifier module 512, and the A/D converter 516 are controlled by acontrol portion 517.

The living body passing light intensity signals converted to digitalsignals are recorded in a storage portion 518 provided in the imageproducing portion 521. The living body passing light intensity signalsrecorded in the storage portion 518 are read at a processing portion 519which is also provided in the image producing portion 521. In the caseof an ordinary living body optical measurement, the processing portion519 computes changes in oxygenated hemoglobin concentration and changesin de-oxygenated hemoglobin concentration accompanying brain activity,and hemoglobin concentration total amount, based on the living bodypassing light intensity signals of the detecting positions. Thecomputation results are displayed on a display screen (not shown) of theinput/output portion 520 as age-based information on a plurality ofmeasurement positions. The age-based information is stored in thestorage portion 518. The method of computation by the processing portion519 is well known in the art, so a detailed description thereof will beomitted.

In the living body passing light measuring device constructed asdescribed above, the tip portions of the irradiation and detectionoptical fibers 102 and 103 are introduced into the probe main body 101,and are bent inside the probe main body 101 so as to be perpendicular tothe skin of the subject. Thus, even when the subject is in a proneposition, it is possible to perform living body optical measurementwithout damaging the measuring probe (in particular, the irradiation anddetection optical fibers 102 and 103).

As a result, it is also possible to perform a living body opticalmeasurement which takes so long as to necessitate the subject to take arest, such as sleep, which has been difficult in a living body opticalmeasurement using a conventional measuring probe. Thus, it is possibleto accurately identify the position of a hypnic epileptic focus or thelike, which has conventionally been difficult to identify, making itpossible to achieve a substantial improvement in terms of therapeuticperformance.

Further, since only the core portions of the optical fibers 102 and 103are accommodated in the holder portion 104, it is possible to bend theoptical fibers 102 and 103 at a smaller radius, making it possible toreduce the thickness of the holder portion 104. As a result, it ispossible to further reduce the burden on the subject when performingmeasurement with the subject lied down.

Further, since the holder base 201 is formed of a material more flexiblethan that of the holder cover 202, it is possible to further reduce theburden on the subject at the time of attachment.

The number of holder portions 104 is not restricted to three but may beany other number.

Further, the number of optical fibers arranged in one holder portion 104is not restricted to three, either, but may be any other number.

Further, the routing of the optical fibers 102 and 103 in the holderportion 104 is not restricted to the above-described one.

Furthermore, while in this embodiment the annular protrusions 403 areformed so as to protrude from the holder base 201, this should not beconstrued restrictively; for example, it is also possible to form theannular recesses 403 by forming recesses extending in the minor axisdirection of the holder base 201.

The values of the wavelengths of the lights emitted from the opticalmodules 502 are not restricted to 780 nm and 830 nm. Further, the numberof wavelengths is not restricted to two, either.

Further, while in the above example a semiconductor laser is used as thelight source, this should not be construed restrictively; for example,it is also possible to use a light emitting diode.

Furthermore, the method of modulation at the oscillating portion 503 isnot restricted to the analog modulation by sine wave; it may also be,for example, a digital modulation using rectangular waves of differenttime intervals. When thus using digital modulation, a digital filter ora digital signal processor is used as a modulated signal detectingmeans.

Further, the photo detectors are not restricted to photo diodes; it isalso possible to use other photoelectric conversion devices, such asphotomultiplier tubes, as long as they are photoelectric conversiondevices.

Embodiment 2

Next, FIG. 11 is a front view of a measuring probe according toEmbodiment 2 of the present invention, FIG. 12 is a sectional view takenalong the line XII-XII of FIG. 11, and FIG. 13 is a perspective view ofthe measuring probe of FIG. 11 with the holder cover removed therefrom.

In Embodiment 2, in order to match the holder portion 104 with the headconfiguration of the subject, a base plate 601 as a curving means isbonded to the holder portion 104. The construction of the holder portion104 is the same as that of Embodiment 1. The base plate 601 is formed ofa hard material, such as plastic. Thus, the holder portion 104 isreinforced by the base plate 601.

The base plate 601 is curved in advance. The curvature of the base plate601 is matched with the head configuration of the subject in advance.The holder portion 104 is maintained in a configuration corresponding tothe curved configuration of the base plate 601. Further, the base plate601 is constructed so as not to interfere with the annular protrusions403 and the distal end portions of the optical fibers 102 and 103.

By using the base plate 601 described above, it is possible to securethe holder portion 104 in position in a state in which the holderportion 104 is in close contact with the head of the subject. Thus,there is no fear of any undesired gap being generated between the headof the subject and the holder portion 104, making it possible to achievean improvement in terms of measurement sensitivity.

Further, although not shown, it is also possible to provide rails on thesubject side of the holder portion 104, holding the base plate 601between the rails. This makes it possible to replace the base plate 601and to combine the relatively soft holder portion 104 with base plates601 of various configurations, making it possible to modify and attachthe holder portion 104 in an optimum manner in conformity with varioussubject head configurations.

FIG. 14 is a perspective view of the holder portions 104 of FIG. 11 asattached to the subject, and FIG. 15 is a perspective view of the holderportions 104 of FIG. 14 with a fastening fixing member 701 attached fromabove.

The holder portions 104 are combined with base plates 601 ofconfigurations corresponding to their respective attachment positions.This makes it possible for the holder portions 104 to be fixed in anoptimum conformity with the head, which exhibits a fine variation inconfiguration from position to position.

Further, by attaching the tube-shaped fastening fixing member 701surrounding the subject, it is possible to prevent the holder portions104 from being detached, and to hold the holder portions 104 in closecontact with the subject. As the material of the fastening fixing member701, it is possible to use an elastic cloth, a ring-like balloon adaptedto expand through injection of air, etc.

The base plates 601 are equipped with connecting portions 602 for theconnection of the adjacent base plates 601. The connecting portions 602may be, for example, of the type in which protrusions and holes arejoined with each other or of the type in which attachment is effected byusing magnets. This helps to prevent the individual holder portions 104from being detached.

Further, a connection hole 603 is provided at an end of each base plate601. It is possible to connect a chin strap or belt (not shown) for thesubject to the connection hole 603 as needed.

While in Embodiment 2 the base plate 601 and the holder base 201 areseparate from each other, it is also possible to mold the base plate 601and the holder base 201 integrally with each other.

Further, the base plate may be formed of a material which allows freemanual curving and maintenance of the curved state. This makes itpossible to perform attachment with the holder portions deformed in anoptimum fashion in conformity with various subject head configurationswithout having to replace the base plates. In this case, the holderportions are formed of a material more flexible than that of the baseplates, and are curved in conformity with the curving of the base plateswithout hindering the maintenance of the curved state of the baseplates.

Embodiment 3

Next, FIG. 16 is a plan view of a measuring probe according toEmbodiment 3 of the present invention. While in Embodiment 1 a pluralityof holder portions 104 are connected by the connecting portions 105, inEmbodiment 3, a plurality of holder portions 104 are previously formedinto an integral unit. In this case, at least either the holder bases201 or the holder covers 202 adopt an integral structure.

Due to this construction, it is possible to achieve a reduction in thenumber of parts, and to more reliably prevent mutual positionaldeviation of the holder portions 104.

Embodiment 4

Next, FIG. 17 is a plan view of a measuring probe according toEmbodiment 4 of the present invention. In this embodiment, the measuringprobe as a whole is formed such that the distal end portions of theirradiation optical fibers 102 and the distal end portions of thedetection optical fibers 103 are arranged alternately in both thelongitudinal direction of the holder portions 104 (the horizontaldirection in FIG. 17) and the direction perpendicular to thelongitudinal direction of the holder portions 104. Further, a fixeddistance is maintained between the adjacent holder portions 104 by theconnecting portions 105.

In the measuring probe described above, the distal end portions of theoptical fibers 102 and 103 are arranged in a tetragonal-lattice-likefashion, and the distal end portions of the irradiation optical fibers102 and the distal end portions of the detection optical fibers 103 arearranged alternately in both of the two directions perpendicular to eachother, whereby it is possible to realize a more effective measurement.

1. A measuring probe comprising: a holder portion which is adapted to beattached to a subject; and an optical fiber for at least one ofirradiation and detection, whose distal end portion on a subject side isretained by the holder portion; wherein the optical fiber is led outfrom a side surface of the holder portion and is bent inside the holderportion such that the distal end portion is directed to the subject whenthe holder portion is attached to the subject; wherein an optical fiberfixing member which fixes the distal end portion of the optical fiber isarranged in the holder portion; and wherein an optical fiber protectingmember which protects the bent portion of the optical fiber is arrangedinside the holder portion.
 2. A measuring probe according to claim 1,wherein an outer peripheral coating is removed from the bent portion ofthe optical fiber inside the holder portion.
 3. A measuring probeaccording to claim 1, wherein the holder portion has a first member tobe brought into contact with the subject and a second member combinedwith the first member.
 4. A measuring probe according to claim 3,wherein the first member is more flexible than the second member, andwherein the second member is more rigid than the first member.
 5. Ameasuring probe according to claim 3, wherein a protecting groove intowhich the optical fiber is inserted is formed in at least one of thefirst member and the second member.
 6. A measuring probe according toclaim 1, wherein the holder portion is provided with a through-holethrough which the distal end portion of the optical fiber is exposed andan annular protrusion protruding so as to surround the distal endportion of the optical fiber.
 7. A measuring probe according to claim 1,wherein a space portion for accommodating the bent portion of theoptical fiber is provided inside the holder portion.
 8. A measuringprobe according to claim 7, wherein the holder portion has a firstmember to be brought into contact with the subject and a second membercombined with the first member, and wherein the space portion is formedby combining recesses respectively provided in the first and secondmembers.
 9. A measuring probe according to claim 1, wherein a spaceportion for accommodating the bent portion of the optical fiber and theoptical fiber fixing member is provided in the holder portion, andwherein a diameter of the space portion is of the same size as an outerperipheral diameter of the optical fiber fixing member.
 10. A measuringprobe according to claim 1, wherein a height adjustment jig foradjusting an amount by which the optical fiber protrudes from the holderportion is arranged inside the holder portion.
 11. A measuring probeaccording to claim 1, further comprising a curving means provided on theholder portion, for maintaining the holder portion in a configurationcurved along the subject.
 12. A measuring probe according to claim 11,wherein the curving means is mounted to the subject side of the holderportion and is a base plate curved in advance.
 13. A measuring probeaccording to claim 11, wherein the curving means is replaceable withrespect to the holder portion.
 14. A measuring probe according to claim11, wherein the curving means is provided with a connecting portion forconnection with an adjacent curving means.
 15. A living body opticalmeasuring device comprising: a measuring probe having: a plurality ofoptical fibers that irradiate a subject with measurement light andreceive the measurement light returning from the subject, and a holderportion which is adapted to attach the measuring probe to the subject;wherein the optical fibers are led out from a side surface of themeasuring probe and are bent inside the holder portion such that theirdistal end portions are directed towards the subject when the holderportion attaches the measuring probe to the subject; wherein an opticalfiber fixing member which fixes the distal end portion of the opticalfibers is arranged in the holder portion; and wherein an optical fiberprotecting member which protects the bent portion of the optical fibersis arranged inside the holder portion.
 16. A living body opticalmeasuring device according to claim 15, wherein the measuring probe hasa plurality of holder portions, wherein in each of the plurality ofholder portions, the distal end portions of the plurality of opticalfibers are arranged at intervals.
 17. A living body optical measuringdevice according to claim 15, further comprising a fastening fixingmember which is adapted to be put on the subject from above themeasuring probe so as to surround the subject and which prevents themeasuring probe from being detached from the subject.
 18. A measuringprobe comprising: a holder portion which is adapted to attach to asubject; and an optical fiber for at least one of irradiation anddetection, the optical fiber having a distal end portion on a subjectside which is retained by the holder portion; wherein the optical fiberis led out from a side surface of the holder portion and is bent insidethe holder portion so that the distal end portion is directed to thesubject when the holder portion is attached to the subject; and whereinan optical fiber protecting member which protects the bent portion ofthe optical fiber is arranged inside the holder portion.